Alright, let's solve this math problem step by step. First, we have the number 84. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 400. So, we're going to take the number 84 and add it to itself 400 times.
Step 1: 0 + 84 = 84
Step 2: 84 + 84 = 168
Step 3: 168 + 84 = 252
Step 4: 252 + 84 = 336
Step 5: 336 + 84 = 420
Step 6: 420 + 84 = 504
Step 7: 504 + 84 = 588
Step 8: 588 + 84 = 672
Step 9: 672 + 84 = 756
Step 10: 756 + 84 = 840
Step 11: 840 + 84 = 924
Step 12: 924 + 84 = 1008
Step 13: 1008 + 84 = 1092
Step 14: 1092 + 84 = 1176
Step 15: 1176 + 84 = 1260
Step 16: 1260 + 84 = 1344
Step 17: 1344 + 84 = 1428
Step 18: 1428 + 84 = 1512
Step 19: 1512 + 84 = 1596
Step 20: 1596 + 84 = 1680
Step 21: 1680 + 84 = 1764
Step 22: 1764 + 84 = 1848
Step 23: 1848 + 84 = 1932
Step 24: 1932 + 84 = 2016
Step 25: 2016 + 84 = 2100
Step 26: 2100 + 84 = 2184
Step 27: 2184 + 84 = 2268
Step 28: 2268 + 84 = 2352
Step 29: 2352 + 84 = 2436
Step 30: 2436 + 84 = 2520
Step 31: 2520 + 84 = 2604
Step 32: 2604 + 84 = 2688
Step 33: 2688 + 84 = 2772
Step 34: 2772 + 84 = 2856
Step 35: 2856 + 84 = 2940
Step 36: 2940 + 84 = 3024
Step 37: 3024 + 84 = 3108
Step 38: 3108 + 84 = 3192
Step 39: 3192 + 84 = 3276
Step 40: 3276 + 84 = 3360
Step 41: 3360 + 84 = 3444
Step 42: 3444 + 84 = 3528
Step 43: 3528 + 84 = 3612
Step 44: 3612 + 84 = 3696
Step 45: 3696 + 84 = 3780
Step 46: 3780 + 84 = 3864
Step 47: 3864 + 84 = 3948
Step 48: 3948 + 84 = 4032
Step 49: 4032 + 84 = 4116
Step 50: 4116 + 84 = 4200
Step 51: 4200 + 84 = 4284
Step 52: 4284 + 84 = 4368
Step 53: 4368 + 84 = 4452
Step 54: 4452 + 84 = 4536
Step 55: 4536 + 84 = 4620
Step 56: 4620 + 84 = 4704
Step 57: 4704 + 84 = 4788
Step 58: 4788 + 84 = 4872
Step 59: 4872 + 84 = 4956
Step 60: 4956 + 84 = 5040
Step 61: 5040 + 84 = 5124
Step 62: 5124 + 84 = 5208
Step 63: 5208 + 84 = 5292
Step 64: 5292 + 84 = 5376
Step 65: 5376 + 84 = 5460
Step 66: 5460 + 84 = 5544
Step 67: 5544 + 84 = 5628
Step 68: 5628 + 84 = 5712
Step 69: 5712 + 84 = 5796
Step 70: 5796 + 84 = 5880
Step 71: 5880 + 84 = 5964
Step 72: 5964 + 84 = 6048
Step 73: 6048 + 84 = 6132
Step 74: 6132 + 84 = 6216
Step 75: 6216 + 84 = 6300
Step 76: 6300 + 84 = 6384
Step 77: 6384 + 84 = 6468
Step 78: 6468 + 84 = 6552
Step 79: 6552 + 84 = 6636
Step 80: 6636 + 84 = 6720
Step 81: 6720 + 84 = 6804
Step 82: 6804 + 84 = 6888
Step 83: 6888 + 84 = 6972
Step 84: 6972 + 84 = 7056
Step 85: 7056 + 84 = 7140
Step 86: 7140 + 84 = 7224
Step 87: 7224 + 84 = 7308
Step 88: 7308 + 84 = 7392
Step 89: 7392 + 84 = 7476
Step 90: 7476 + 84 = 7560
Step 91: 7560 + 84 = 7644
Step 92: 7644 + 84 = 7728
Step 93: 7728 + 84 = 7812
Step 94: 7812 + 84 = 7896
Step 95: 7896 + 84 = 7980
Step 96: 7980 + 84 = 8064
Step 97: 8064 + 84 = 8148
Step 98: 8148 + 84 = 8232
Step 99: 8232 + 84 = 8316
Step 100: 8316 + 84 = 8400
Step 101: 8400 + 84 = 8484
Step 102: 8484 + 84 = 8568
Step 103: 8568 + 84 = 8652
Step 104: 8652 + 84 = 8736
Step 105: 8736 + 84 = 8820
Step 106: 8820 + 84 = 8904
Step 107: 8904 + 84 = 8988
Step 108: 8988 + 84 = 9072
Step 109: 9072 + 84 = 9156
Step 110: 9156 + 84 = 9240
Step 111: 9240 + 84 = 9324
Step 112: 9324 + 84 = 9408
Step 113: 9408 + 84 = 9492
Step 114: 9492 + 84 = 9576
Step 115: 9576 + 84 = 9660
Step 116: 9660 + 84 = 9744
Step 117: 9744 + 84 = 9828
Step 118: 9828 + 84 = 9912
Step 119: 9912 + 84 = 9996
Step 120: 9996 + 84 = 10080
Step 121: 10080 + 84 = 10164
Step 122: 10164 + 84 = 10248
Step 123: 10248 + 84 = 10332
Step 124: 10332 + 84 = 10416
Step 125: 10416 + 84 = 10500
Step 126: 10500 + 84 = 10584
Step 127: 10584 + 84 = 10668
Step 128: 10668 + 84 = 10752
Step 129: 10752 + 84 = 10836
Step 130: 10836 + 84 = 10920
Step 131: 10920 + 84 = 11004
Step 132: 11004 + 84 = 11088
Step 133: 11088 + 84 = 11172
Step 134: 11172 + 84 = 11256
Step 135: 11256 + 84 = 11340
Step 136: 11340 + 84 = 11424
Step 137: 11424 + 84 = 11508
Step 138: 11508 + 84 = 11592
Step 139: 11592 + 84 = 11676
Step 140: 11676 + 84 = 11760
Step 141: 11760 + 84 = 11844
Step 142: 11844 + 84 = 11928
Step 143: 11928 + 84 = 12012
Step 144: 12012 + 84 = 12096
Step 145: 12096 + 84 = 12180
Step 146: 12180 + 84 = 12264
Step 147: 12264 + 84 = 12348
Step 148: 12348 + 84 = 12432
Step 149: 12432 + 84 = 12516
Step 150: 12516 + 84 = 12600
Step 151: 12600 + 84 = 12684
Step 152: 12684 + 84 = 12768
Step 153: 12768 + 84 = 12852
Step 154: 12852 + 84 = 12936
Step 155: 12936 + 84 = 13020
Step 156: 13020 + 84 = 13104
Step 157: 13104 + 84 = 13188
Step 158: 13188 + 84 = 13272
Step 159: 13272 + 84 = 13356
Step 160: 13356 + 84 = 13440
Step 161: 13440 + 84 = 13524
Step 162: 13524 + 84 = 13608
Step 163: 13608 + 84 = 13692
Step 164: 13692 + 84 = 13776
Step 165: 13776 + 84 = 13860
Step 166: 13860 + 84 = 13944
Step 167: 13944 + 84 = 14028
Step 168: 14028 + 84 = 14112
Step 169: 14112 + 84 = 14196
Step 170: 14196 + 84 = 14280
Step 171: 14280 + 84 = 14364
Step 172: 14364 + 84 = 14448
Step 173: 14448 + 84 = 14532
Step 174: 14532 + 84 = 14616
Step 175: 14616 + 84 = 14700
Step 176: 14700 + 84 = 14784
Step 177: 14784 + 84 = 14868
Step 178: 14868 + 84 = 14952
Step 179: 14952 + 84 = 15036
Step 180: 15036 + 84 = 15120
Step 181: 15120 + 84 = 15204
Step 182: 15204 + 84 = 15288
Step 183: 15288 + 84 = 15372
Step 184: 15372 + 84 = 15456
Step 185: 15456 + 84 = 15540
Step 186: 15540 + 84 = 15624
Step 187: 15624 + 84 = 15708
Step 188: 15708 + 84 = 15792
Step 189: 15792 + 84 = 15876
Step 190: 15876 + 84 = 15960
Step 191: 15960 + 84 = 16044
Step 192: 16044 + 84 = 16128
Step 193: 16128 + 84 = 16212
Step 194: 16212 + 84 = 16296
Step 195: 16296 + 84 = 16380
Step 196: 16380 + 84 = 16464
Step 197: 16464 + 84 = 16548
Step 198: 16548 + 84 = 16632
Step 199: 16632 + 84 = 16716
Step 200: 16716 + 84 = 16800
Step 201: 16800 + 84 = 16884
Step 202: 16884 + 84 = 16968
Step 203: 16968 + 84 = 17052
Step 204: 17052 + 84 = 17136
Step 205: 17136 + 84 = 17220
Step 206: 17220 + 84 = 17304
Step 207: 17304 + 84 = 17388
Step 208: 17388 + 84 = 17472
Step 209: 17472 + 84 = 17556
Step 210: 17556 + 84 = 17640
Step 211: 17640 + 84 = 17724
Step 212: 17724 + 84 = 17808
Step 213: 17808 + 84 = 17892
Step 214: 17892 + 84 = 17976
Step 215: 17976 + 84 = 18060
Step 216: 18060 + 84 = 18144
Step 217: 18144 + 84 = 18228
Step 218: 18228 + 84 = 18312
Step 219: 18312 + 84 = 18396
Step 220: 18396 + 84 = 18480
Step 221: 18480 + 84 = 18564
Step 222: 18564 + 84 = 18648
Step 223: 18648 + 84 = 18732
Step 224: 18732 + 84 = 18816
Step 225: 18816 + 84 = 18900
Step 226: 18900 + 84 = 18984
Step 227: 18984 + 84 = 19068
Step 228: 19068 + 84 = 19152
Step 229: 19152 + 84 = 19236
Step 230: 19236 + 84 = 19320
Step 231: 19320 + 84 = 19404
Step 232: 19404 + 84 = 19488
Step 233: 19488 + 84 = 19572
Step 234: 19572 + 84 = 19656
Step 235: 19656 + 84 = 19740
Step 236: 19740 + 84 = 19824
Step 237: 19824 + 84 = 19908
Step 238: 19908 + 84 = 19992
Step 239: 19992 + 84 = 20076
Step 240: 20076 + 84 = 20160
Step 241: 20160 + 84 = 20244
Step 242: 20244 + 84 = 20328
Step 243: 20328 + 84 = 20412
Step 244: 20412 + 84 = 20496
Step 245: 20496 + 84 = 20580
Step 246: 20580 + 84 = 20664
Step 247: 20664 + 84 = 20748
Step 248: 20748 + 84 = 20832
Step 249: 20832 + 84 = 20916
Step 250: 20916 + 84 = 21000
Step 251: 21000 + 84 = 21084
Step 252: 21084 + 84 = 21168
Step 253: 21168 + 84 = 21252
Step 254: 21252 + 84 = 21336
Step 255: 21336 + 84 = 21420
Step 256: 21420 + 84 = 21504
Step 257: 21504 + 84 = 21588
Step 258: 21588 + 84 = 21672
Step 259: 21672 + 84 = 21756
Step 260: 21756 + 84 = 21840
Step 261: 21840 + 84 = 21924
Step 262: 21924 + 84 = 22008
Step 263: 22008 + 84 = 22092
Step 264: 22092 + 84 = 22176
Step 265: 22176 + 84 = 22260
Step 266: 22260 + 84 = 22344
Step 267: 22344 + 84 = 22428
Step 268: 22428 + 84 = 22512
Step 269: 22512 + 84 = 22596
Step 270: 22596 + 84 = 22680
Step 271: 22680 + 84 = 22764
Step 272: 22764 + 84 = 22848
Step 273: 22848 + 84 = 22932
Step 274: 22932 + 84 = 23016
Step 275: 23016 + 84 = 23100
Step 276: 23100 + 84 = 23184
Step 277: 23184 + 84 = 23268
Step 278: 23268 + 84 = 23352
Step 279: 23352 + 84 = 23436
Step 280: 23436 + 84 = 23520
Step 281: 23520 + 84 = 23604
Step 282: 23604 + 84 = 23688
Step 283: 23688 + 84 = 23772
Step 284: 23772 + 84 = 23856
Step 285: 23856 + 84 = 23940
Step 286: 23940 + 84 = 24024
Step 287: 24024 + 84 = 24108
Step 288: 24108 + 84 = 24192
Step 289: 24192 + 84 = 24276
Step 290: 24276 + 84 = 24360
Step 291: 24360 + 84 = 24444
Step 292: 24444 + 84 = 24528
Step 293: 24528 + 84 = 24612
Step 294: 24612 + 84 = 24696
Step 295: 24696 + 84 = 24780
Step 296: 24780 + 84 = 24864
Step 297: 24864 + 84 = 24948
Step 298: 24948 + 84 = 25032
Step 299: 25032 + 84 = 25116
Step 300: 25116 + 84 = 25200
Step 301: 25200 + 84 = 25284
Step 302: 25284 + 84 = 25368
Step 303: 25368 + 84 = 25452
Step 304: 25452 + 84 = 25536
Step 305: 25536 + 84 = 25620
Step 306: 25620 + 84 = 25704
Step 307: 25704 + 84 = 25788
Step 308: 25788 + 84 = 25872
Step 309: 25872 + 84 = 25956
Step 310: 25956 + 84 = 26040
Step 311: 26040 + 84 = 26124
Step 312: 26124 + 84 = 26208
Step 313: 26208 + 84 = 26292
Step 314: 26292 + 84 = 26376
Step 315: 26376 + 84 = 26460
Step 316: 26460 + 84 = 26544
Step 317: 26544 + 84 = 26628
Step 318: 26628 + 84 = 26712
Step 319: 26712 + 84 = 26796
Step 320: 26796 + 84 = 26880
Step 321: 26880 + 84 = 26964
Step 322: 26964 + 84 = 27048
Step 323: 27048 + 84 = 27132
Step 324: 27132 + 84 = 27216
Step 325: 27216 + 84 = 27300
Step 326: 27300 + 84 = 27384
Step 327: 27384 + 84 = 27468
Step 328: 27468 + 84 = 27552
Step 329: 27552 + 84 = 27636
Step 330: 27636 + 84 = 27720
Step 331: 27720 + 84 = 27804
Step 332: 27804 + 84 = 27888
Step 333: 27888 + 84 = 27972
Step 334: 27972 + 84 = 28056
Step 335: 28056 + 84 = 28140
Step 336: 28140 + 84 = 28224
Step 337: 28224 + 84 = 28308
Step 338: 28308 + 84 = 28392
Step 339: 28392 + 84 = 28476
Step 340: 28476 + 84 = 28560
Step 341: 28560 + 84 = 28644
Step 342: 28644 + 84 = 28728
Step 343: 28728 + 84 = 28812
Step 344: 28812 + 84 = 28896
Step 345: 28896 + 84 = 28980
Step 346: 28980 + 84 = 29064
Step 347: 29064 + 84 = 29148
Step 348: 29148 + 84 = 29232
Step 349: 29232 + 84 = 29316
Step 350: 29316 + 84 = 29400
Step 351: 29400 + 84 = 29484
Step 352: 29484 + 84 = 29568
Step 353: 29568 + 84 = 29652
Step 354: 29652 + 84 = 29736
Step 355: 29736 + 84 = 29820
Step 356: 29820 + 84 = 29904
Step 357: 29904 + 84 = 29988
Step 358: 29988 + 84 = 30072
Step 359: 30072 + 84 = 30156
Step 360: 30156 + 84 = 30240
Step 361: 30240 + 84 = 30324
Step 362: 30324 + 84 = 30408
Step 363: 30408 + 84 = 30492
Step 364: 30492 + 84 = 30576
Step 365: 30576 + 84 = 30660
Step 366: 30660 + 84 = 30744
Step 367: 30744 + 84 = 30828
Step 368: 30828 + 84 = 30912
Step 369: 30912 + 84 = 30996
Step 370: 30996 + 84 = 31080
Step 371: 31080 + 84 = 31164
Step 372: 31164 + 84 = 31248
Step 373: 31248 + 84 = 31332
Step 374: 31332 + 84 = 31416
Step 375: 31416 + 84 = 31500
Step 376: 31500 + 84 = 31584
Step 377: 31584 + 84 = 31668
Step 378: 31668 + 84 = 31752
Step 379: 31752 + 84 = 31836
Step 380: 31836 + 84 = 31920
Step 381: 31920 + 84 = 32004
Step 382: 32004 + 84 = 32088
Step 383: 32088 + 84 = 32172
Step 384: 32172 + 84 = 32256
Step 385: 32256 + 84 = 32340
Step 386: 32340 + 84 = 32424
Step 387: 32424 + 84 = 32508
Step 388: 32508 + 84 = 32592
Step 389: 32592 + 84 = 32676
Step 390: 32676 + 84 = 32760
Step 391: 32760 + 84 = 32844
Step 392: 32844 + 84 = 32928
Step 393: 32928 + 84 = 33012
Step 394: 33012 + 84 = 33096
Step 395: 33096 + 84 = 33180
Step 396: 33180 + 84 = 33264
Step 397: 33264 + 84 = 33348
Step 398: 33348 + 84 = 33432
Step 399: 33432 + 84 = 33516
Step 400: 33516 + 84 = 33600

So, 84*400 = 33600